The 呼吸条 appears when a player's head is under either 水 or 蜂蜜, representing the time the player has until they begin drowning. The Breath Meter consists of ten air bubbles (five on the 移动版) that fade and disappear gradually as long as the character's head is submerged. When the Breath Meter is depleted, the player begins to drown and health is depleted. The Breath Meter refills quickly when the player emerges from liquid.
For breathing purposes, the player is considered "under water" when the pixel right above their eye is under water. This roughly correlates to just a pixel above where the water will be if the player stands in two full tiles of water with a tile of air in the third tile they occupy. Half-blocks can leave players drowning. In older versions and 主机版s, this was actually the very top pixel of the head. It was changed to prevent players from drowning when their head bumped water-filled blocks.
The Breath Meter's duration changes depending on which breathing equipment or potions are used. Times shown below are in real-world time (not game time):